The present invention relates to steering wheel stroking systems, and more particularly, to a steering wheel stroking system and method of energy absorption utilizing active material actuation.
To reduce risk of injury to the driver during a crash event, conventional steering columns often feature energy-absorbing elements, such as a collapsible steering shaft, and break away mounting features. These features, more particularly, enable the steering column to give upon impact with the driver, in what is also known as “steering wheel stroking.” While increasing safety, however, these features typically present one-size-fits-all allowances, wherein the rate of energy-absorption remains constant regardless of event or driver characteristics. Of further concern, the irreversible shearing and deformation typically provided by these systems result in one-time usage, which necessitates repair and/or the replacement of parts after use.
An energy absorption system wherein a variable damper is externally coupled to the column and driven by air-bag deployment has also been developed, but this system also presents concerns. For example, the addition of external structure creates packaging challenges in the typically tight spacing afforded steering columns. Moreover, with respect to driver safety it is appreciated that stroking optimization occurs near the end of or subsequent to, as opposed to at the beginning of, typical air bag deployment.